The invention relates to a method for determining the vector components such as X and Y or the magnitude and phase of an oscillation represented by a measured signal accompanied by interfering signals, whereby a reference signal is used. The invention also relates to a circuit arrangement for performing the method. The interfering signals are a mixture of oscillations.
Vibrational analysis poses the problem to determine individual frequency components or vibrations from a mixture of vibrations. Mathematical methods such as the harmonic analysis for solving this problem are known. Similarly, the technological means for the realization of these methods are also known. In balancing techniques such methods are, for example, the wattmeter measuring method, the Hall multiplication method, and the controlled rectification method.
The vibrational spectrum or mixture of vibrations to be analyzed is usually an electrical, measured signal in the form of a voltage, for example. In other instances, the vibration mixture may be converted to an electrical measured signal. The mixture of vibrations generally includes in addition to the oscillation or frequency of interest, a plurality of interfering vibrations which have different amplitudes and frequencies and which must be suppressed or separated. Methods for performing such suppression or separation are known in the prior art.
According to one prior art method the measured signal is combined with a reference signal by multiplying the two signals with each other by electrical means and then integrated. In this way the X and Y components of the oscillation of interest in an orthogonal coordinate system, or the magnitude and phase position of the oscillation of interest in a polar coordinate system vibration, are obtained. The oscillation of interest may, for example, be an unbalance vibration.
Prior art methods have the disadvantage that the formation of the product of the measured signal and therefore signal is more or less subject to errors. Especially, zero point errors occur easily. Besides, the technological realization of the mentioned prior art methods is rather involved and hence quite expensive.